Abstract 5089: RNF43 mutation as a predictor of immunotherapeutic efficacy in colorectal cancer

Abstract

Abstract Background: RNF43, a single transmembrane circular E3 ubiquitin ligase, has been identified as a tumor suppressor for a variety of cancers, including ovarian cancer, gastric cancer, pancreatic cancer, endometrial cancer and colorectal cancer. It is even considered to be carcinogenic driver mutations in cholangiocarcinoma, ovarian cancer, gastric cancer, endometrial cancer and colorectal cancer (CRC). However, the correlation between RNF43 mutation and CRC immunotherapy has not been reported yet. Methods: We evaluated the role of RNF43 in CRC using publicly available data from The Cancer Genome Atlas (TCGA) and Memorial Sloan Kettering Cancer Center (MSKCC). An in-house Chinese CRC cohort (n=2290) was used for the analysis of immune-related markers. The relationship between clinical pathologic features and RNF43 were analyzed with using the two-sided chi-squared test or the Fisher exact test. Clinicopathologic characteristics associated with overall survival using Cox regression and the Kaplan-Meier method. Results: In the MSKCC cohort, a total of 108 CRC patients receiving immunotherapy were enrolled, of which 38 (34.9%) were over 60-year-old and 61 (56.0%) were male. RNF43 mutation was significantly associated with high TMB and high MSI score (all p <0.05). Besides these, RNF43 mutation was discovered to be enriched in MSI instable. Kaplan-Meier survival analysis showed that patients with RNF43 mutation obtained better OS compared to RNF43 wild-type (not reach vs. 13 months, HR, 0.12; 95% CI 0.03-0.49; p=0.0034). In the TCGA cohort, CRC patients of stage I-IV were 16.6%, 38.5%, 28.2% and 14.2%, respectively. All of these patients received radiation therapy. No association was observed between RNF43 and OS (HR, 1.83; 95% CI 0.66-5.07; p=0.2479). In the in-house Chinese CRC cohorts, 210 (9.2%) patients carried RNF 43 mutations, of which 123 patients (58.6%) were male. RNF43 mutations were significantly associated with higher TMB levels (p<0.0001) and PD-L1 TPS> 1% (p=0.0110) in the in-house Chinese RCC cohorts. Citation Format: Changjun Yu, Weibiao Kang, Yu Yuan, Junling Zhang, Mengli Huang, Yanan Chen, Xihua Xia, Yuezong Bai. RNF43 mutation as a predictor of immunotherapeutic efficacy in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5089.